ADHD and Autism are interesting, because they are entirely based on certain clinical presentations and the opinion of the diagnosing practitioner. There are a certain set of traits that are "classically" ADHD for example, so what happens if you show 80% of those traits and show the counter-case for 20% of the traits? I expect that neurodivergence is going to become far more nuanced in its assessment, with a better understanding of an individual's whole psychological profile.
In the Cincinnati area they throw up their hands if you are over the age of 12 and suspect ADHD. There is little to no help if you are an adult or close to it.
You can literally see ADHD in a brain scan, especially if you contrast it with after someone has taken the proper medication for it. This isn't some sort of witchcraft, it's a physical thing that's measurable.
That's not how you get diagnosed however, nor do I know if you would receive a diagnosis of adhd when a brain scan shows behavior similar to that of ADHD but you show no symptoms and aren't seeking a diagnosis. If you go in for an ADHD evaluation you typically get a psychological assessment, potentially do some tests which aren't always conclusive and your symptoms will be evaluated. In that sense, it's not really measurable in the same way that we can test for a specific disease, infection or virus.
It's not a strict relationship as far as I understand though. As in, frontal lobe issues are visible on many brain scans, but those brain scans are not specific enough to map onto ADHD diagnosis. So we don't have a good diagnostic test right now even though we have many population-level confirmed differences that we can run tests and statistics on.
